No question in my mind, the SSD is superior.
The momentus speeds up reads, but with only 32gb, not all of your data will be in the cache, available for a fast read.
And, when it comes time to write, you are still limited by the mechanical speed of the hard drive.
It seserves a place in a laptop where you are limited to one drive, and a ssd won't hold it all.
In a desktop, start with a ssd, and later add a hard drive for bulk storage if you need to.